Nortel Networks 1000 User Manual
Page 228
228
NT5D11 and NT5D14 Lineside T1 Interface cards
faceplate lights and an alarm message is created in the alarm log and
the MMI terminal.
•
Alarm Level 2 (AL2) consists of activity with an error threshold above
the AL2 setting. This is an unsatisfactory condition. In this situation,
the external alarm hardware is activated by closing the normally
open contact. The RED ALARM LED on the faceplate lights, an
alarm message is created in the alarm log and the MMI terminal. The
Lineside T1 card enters line processing mode and a yellow alarm
message is sent to the CPE/CSU. The Line processing sends the CS
1000E, CS 1000M, and Meridian 1either all "on-hook" or all "off-hook"
signals depending on the dip switch setting of the card.
When the Set Alarm command is used, a prompt appears to configure the
threshold level and duration period for alarm levels 1 and 2.
The threshold value indicates the number of bit errors detected per second
that is necessary to activate the alarm. The T1 link processes at a rate of
approximately 1.5 mb/s. The threshold value can be set between 3 and 9
and can be different for each alarm level. Any other value entered causes
the software to display a "Parameter Invalid" message. The threshold
number entered represents the respective power of 10 as shown in
91 "T1 bit error rate threshold settings" (page 228)
.
Note:
The error rate threshold for a level 2 alarm must be greater (a
smaller power of 10) than for a level 1 alarm.
Table 91
T1 bit error rate threshold settings
Alarm threshold
bit errors per second
in power of 10
Threshold
to set alarm
Allowable
duration periods
10
–3
1,500/second
1–21 seconds
10
–4
150/second
1–218 seconds
10
–5
15/second
1–2148 seconds
10
–6
1.5/second
1–3600 seconds
10
–7
1.5/10 seconds
10–3600 seconds
10
–8
1.5/100 seconds
100–3600 seconds
10
–9
1.5/1000 seconds
1000–3600 seconds
The duration value is set in seconds and can be set from 1 to 3600
seconds (1 hour). This duration value indicates how long the alarm lasts.
Low bit error rates (10-7 through 10-9) are restricted to longer durations
since it takes more than one second to detect an alarm condition above
10-6. Higher bit error rates are restricted to shorter durations because the
MMI error counter fills at 65,000 errors.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311
02.06
Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.